Great Amakumo Peak Achievement
Table of Contents
Overview
The Great Amakumo Peak Achievement is an exploration achievement you can unlock in Seirai Island, Inazuma. The area you need to visit to complete the achievement is located inside the Storm that is raging the island, causing you continuous environmental damage.
To complete all the puzzles successfully and not have to worry about getting killed from the damage over time of the area, it is necessary to first complete the Seirai Stormchasers World Quest of the island and calm the storm.
There are plenty of chests and rewards waiting for you to loot while completing the achievement.

First Puzzle
This is a hidden achievement that you can start by completing a puzzle in the heart of Seirai Island. The puzzle is located on the ground right beneath the Thunder Manifestation platform.
Go to the location and defeat all enemies around the puzzle. To solve it all you have to do is light up the right tiles, as seen in the picture below. Once you light them up, an exquisite chest will spawn and the mechanism nearby will unlock.

Activate the mechanism to drain the water in the lake and reveal a new multi-floor underground area. Jump down there to continue exploring. In the first area there is another mechanism and a few enemies near it.
Defeat the enemies to unlock and use it. This will further drain the water and open new areas in the cavern. Do not forget to loot the Exquisite Chest as well.
Door Switches
You can explore around and defeat the enemies in the area if you wish. Eventually you will reach a red barrier working like a door. This entire area has several similar barriers locking rooms and you will have to use the appropriate switch to bring them down.
Next to the door there is also a seelie, the first of three, that you need to follow around. Use the red switch to bring down the barrier and enter the room. There is a yellow switch inside. Use it to open the room next to it with another red switch.
This new red switch will bring down a barrier upstairs. Use it, get out of the room and use again the yellow switch. Then head upstairs and pass through the two barriers, one red and one yellow, following the seelie.
The seelie will spawn a common chest. Loot it and continue with the second seelie found there.
Drop down and use the yellow switch. Go upstairs and activate the red switch there. There is a hole on the floor nearby, you can use to get back to the seelie. The seelie will go up but before you follow, you need first to use the yellow switch nearby again. Then climb up and continue following the seelie.
Loot the new common chest and follow the third seelie. Eventually it will enter a room blocked by a blue barrier. Other rooms around are blocked with red and yellow barriers. Follow the open path until you find a red switch. Defeat any enemy that spawns and use the switch.
Head downstairs to find the red barrier down and use the blue switch inside that room. Go back upstairs and the blue barrier will be down. Defeat the enemy and get inside the room. Use the yellow switch and get down again.
Follow the path to reach the seelie. At that moment you will unlock the “Great Amakumo Peak” achievement and a mechanism nearby. Loot the Luxurious Chest and get the Electroculus. Activate the mechanism to drain the rest of the water.
Chests
Jump down and continue following the seelie in a room with two chests, a Luxurious and a Precious one. The seelie will also spawn another common chest. Loot them all and use the electrogranum to get out!